Wind damage and even destruction of helicopters and other light aircraft parked on unprotected parking aprons, ramps, and other open sites is a common occurrence. In one recent documented case that occurred at Fort Hood, Tex. on 13 May 1989, a large thunderstorm which produced winds in excess of 60 miles per hour resulted in damage to U.S. Army aircraft estimated to be one-half billion dollars. It also resulted in an enormous burden to the taxpayer and significantly effected the readiness of the nations fighting forces. Although this and other damage from similar occurrences cannot be entirely eliminated, it can be significantly reduced. Current methods used to secure parked aircraft employ tie down devices or placing the aircraft in a protective hangar. The tie down devices have proved to be of limited protection in light to moderate wind conditions but have proven to be ineffective in extreme winds such as mentioned above. Hangars are the ultimate answer but are not always available due to space requirements and cost. The relative flexibility of helicopter rotorblades makes them particularly susceptible to damage. Much of the flexing of these blades is due to the lift they generate as a result of high winds blowing across their surfaces. Even though they are tied down, there is a tremendous tendency to flex up and down causing undue and excessive stress in the entire structure of the blade and the structure to which it is attached. The same stress is exhibited in smaller fixed wing aircraft. Should a tie down device come loose, the airfoil is free to fly. In the case of the helicopter it will flex up and damage the rotorblade itself and other rotor components. Small fixed wing aircraft will become ariborne and possibly be destroyed or damaged by turning over. The major objective of the present invention is to provide a portable, low cost, and effective system for reducing the damage to these aircraft by destroying the lift generating surfaces of the airfoil caused by high relative wind conditions such as that associated with storm gusts and sustained winds.
Previous designs which require many moving parts such as multiple hinges and pins rely on the wind to activate the spoiler system. This system would be subject to failure in the event the metal hinges and pins corrode, bend, or if the system is frozen in the down position caused by ice, snow, or freezing rain conditions. This would leave the aircraft unprotected and the system useless against those winds normally associated with the above mentioned conditions. Previous designs are of such material and size that would either not conform to larger airfoils that droop, as in any large multi-bladed helicopter or require multiple spoilers. One such previous invention described the preferred length to be two feet. This would create an installation problem insofar as the amount of time it would take to install the system, and the fact that the smaller system would require multiple spoilers to adequately perform the purpose it was intended to do. Example in point: The Boeing B-234/U.S. Army CH-47 medium lift helicopter has six main rotorblades which are approximately 28 feet in length. It would require approximately 12 of the above mentioned spoilers per rotorblade with a total of 72 devices to equip the entire aircraft to protect it adequately. This may also prove to be costly when outfitting an entire fleet or even one aircraft for a small owner/operator. Previous designs also appear to be designed with only the small fixed-wing aircraft in mind. The current invention will satisfy the needs of the larger aircraft and the smaller as well. The current invention consists of 3 parts, none moving, and is handled as one modular unit for easy installation and removal. It has application to any size or design airfoil.